Some standard content:
ICS67.060
Agricultural Industry Standard of the People's Republic of China
NY/T1094.2—2006
Wheat experimental milling
Part 2: Biihler method for hard wheat2006-07-10 Issued
2006-10-01 Implementation
The Ministry of Agriculture of the People's Republic of China issued
NY/T1094 Wheat Experimental Milling" is divided into 5 parts: Part 1: Equipment, sample preparation and tempering; for hard wheat;
Part 2: Buhler's method
Part 3: Buhler's method
For soft wheat low extraction rate;
For soft wheat milling;
Part 4: Buhler's method
Part 5: BrabenderQuadrumatJr. (Quadruplex) experimental milling method. This part is Part 2 of NY/T1094.
For hard wheat".
This part corresponds to AACC26-21A:1999 (Experimental milling-Buhler method
Appendices A, B and C of this standard are informative appendices. This standard is proposed and managed by the Ministry of Agriculture of the People's Republic of China. The drafting unit of this standard is: Grain and Product Quality Supervision, Inspection and Testing Center of the Ministry of Agriculture (Harbin). The main drafters of this standard are: Wang Lekai, Cheng Aihua, Zheng Jiafeng, Zhang Yuanpei, Lan Jing, Zhao Naixin and Dai Changjun. NY/T1094.2-2006
1 Scope
Experimental milling of wheat
Part 2: Buhler method for hard wheat
This part specifies the basic principles and methods for using Buhler mill for hard wheat. This part applies to Wheat is processed into wheat flour such as bread or noodles. 2 Normative referenced documents
NY/T1094.2-2006
The clauses in the following documents become the clauses of this part through reference in this part. For any dated referenced documents, all subsequent amendments (excluding errata) or revisions are not applicable to this part. However, parties to agreements based on this part are encouraged to study whether the latest versions of these documents can be used. For any undated referenced documents, the latest versions apply to this part. NY/T1094.1—2006 Wheat experimental milling Part 1 Equipment, sample preparation and wheat tempering 3 Equipment
3.1 Pneumatic conveying laboratory mill
Bihler MLU-20 2 type or equivalent experimental mill, 3.2 Experimental small bran thresher
Buhler MLU-302 type, CW Brabender bran thresher or other experimental bran thresher (optional) 4 Adjustment of experimental mill
4.1 Estimated flour yield
The flour yield of wheat is about 75%, which depends on the characteristics of wheat, degree of cleaning, moisture adjustment, feeding speed, environmental conditions and maintenance of the mill
4.2 Adjustment of roller spring tension
Adjust the length of the spring at both ends of each pair of rollers to 52mm. 4.3 Sieve
4.3.1 For hard wheat, use nitex sieve (aperture expressed in um) or stainless steel sieve with equivalent sieve openings. 1B
|For medium hard wheat, use nitex screen (aperture in um) or stainless steel screen with equivalent mesh size instead. 4.3.2
3For high flour extraction rate, use the following nitex screen (aperture in urn) or stainless steel screen with equivalent mesh size instead. 4.3.3
NY/T1094.2—2006
4.4 Adjustment of screen chain
Adjust the three chains of each screen so that the eccentricity from the center of the chain to each side is 1.25cm. 4.5 Setting of grinding roller
Adjust the rolling distance of the grinding roller after the grinding roller reaches the normal grinding temperature. Before adjustment, cut off the power supply, loosen the nuts on the four handles, rotate the handles, adjust the grinding rollers to be parallel, and use a feeler gauge to make the rolling distance between them 0.1mm. For the skin grinding roller, because the diameter of the first grinding roller is small, the left end of the second skin grinding roller and the right end of the third skin grinding roller should be selected as the measuring points of the feeler gauge. For the center mill, select the left end of the first roller and the right end of the third roller as the measuring point. After accurately adjusting the rollers, tighten the nuts and adjust the dial pointers of the skin mill and the center mill to the scale of 10 (rolling distance 0.1mm = pointer scale 10). Each time the milling experiment is performed, adjust the mill rolling distance to the grinding position. The following scale settings are suitable for most hard wheat:
8~103~5
The final selection of the roller position will vary with the feed rate and the moisture level of the wheat. The size of the roller rolling distance is consistent with the required flour extraction rate. When the setting position of the roller is to be changed during operation, the roller is often loosened first and then pulled to the new scale to avoid errors caused by mechanical vibration. When the first skin mill roller is adjusted to a scraping rate of 6% (through the nitex143 screen), it is suitable for grinding most hard wheat.
4.6 Feeding Rate
The average feeding rate for hard wheat is 130g/min. The feeding rate for soft and floury wheat should be slowed down to less than 100g/min. For hard, brittle wheat, the feeding rate can be increased to 150g/min or more. The best feeding rate for each wheat sample can be determined by adjusting the feeding rate to achieve a satisfactory flour yield. 4.7 Feeding Gate
Adjust the balance weight on the feeding gate to ensure that the material flows evenly to the mill. 5 Operating Procedures
5.1 Environmental Conditions and Sample Preparation
Follow the provisions of Chapter 3 and Chapter 4 of NY/T1094.1-2006. For precautions for Buhler laboratory milling, see Appendix C5.2 Material Removal Method 2
5.2.1 Grinding After the preheated wheat has basically passed through the mill (about 10 minutes) and the laboratory mill is still idling, start cleaning according to the following steps. Tap and brush the air lock and the upper space of the skin mill rollers. Open the mill door and thoroughly clean the lower part of the front and rear rollers, lift the front screen cover and reach to the back of the material channel with a long-handled brush and sweep the material into the flat screen. Clean the center mill in the same way. Clean the skin mill and center mill again. Tap the screen box with a soft rubber hammer or a 3.0 cm diameter hose. Stop the machine and remove the screen. Tap and brush the flour adhering to the material channel under the master screen. Brush the screen and replace it. The experimental mill is ready to grind the next sample. Discard all products of the preheated sample. Clean in the same way after each experimental milling.
5.2.2 Weigh 500g of the tempered wheat sample and record the time when it is poured into the hopper. Use this part of the sample to adjust the feed rate and set the mill. 1) Chinese wheat is mostly medium hardness, and the recommended feed rate is about 100g per minute. 2) To avoid contamination between the two samples and to accurately calculate the maximum flour extraction rate, it is necessary to clean the material left in the mill from the bottom. When the flour characteristics and flour extraction rate are to be accurately determined, the material removal method should be used. When the determination is less accurate, the continuous method that handles a large number of samples has an advantage. When the milling characteristics of the wheat samples vary greatly or the samples contain germinated grains, they should be thoroughly cleaned. If neither of these situations exists, after the feed hopper is empty, the mill continues to operate for 12 minutes. During the cleaning step, the sieve can be brushed continuously and satisfactory results can also be obtained. 2
Roller rolling distance. When the hopper is empty, record the time again and clean the experimental mill as in 5.2.1. NY/T1094.2—2006
5.2.3 Weigh the product and calculate whether the flour extraction rate is appropriate. If it is appropriate, grind the formal sample according to 5.2.2. 1) 5.2.4 The flour extraction rate can be increased by 2% by beating the bran. Bihler MLU-302 bran beater or CW Brabender bran beater or other laboratory bran beater can be used.
5.2.5 Sieve the flour with a 163μmnitex sieve or a stainless steel sieve with the same mesh size and mix the sample in a closed container. Invert the container 25 times or more to mix the sample evenly.
5.2.6 Shake the filter bag after each sample is ground and clean it regularly. 2)5.3 Continuous milling method
5.3.1 Do not stop the mill after grinding the preheated wheat or grinding the previous sample. Put about 1000g of the next moistened wheat sample into the hopper, adjust the feeding speed to ensure good flow of the mill, and adjust the roller spacing if necessary. 5.3.2 When the material distribution is good, accurately collect the flow rate of each product for 1 minute, determine the feeding rate and the percentage of bran, fine bran, and flour. If the degree of satisfaction is achieved, grind 800g~1000g of wheat, tap the flat sieve from time to time with a rubber hammer, and discard all the products. This process not only adjusts the grinding conditions of the wheat sample, but also discharges the residual products of the previous sample out of the experimental mill. Pour the remaining wheat into the hopper, start the timer, and collect the various ground products at the same time. When all the wheat in the hopper has flowed out, accurately record the time and pull out the box for collecting the various ground products. Record the weight of flour at the six powder outlet points, as well as the mass of fine bran and bran. 5.3.3 The total mass of all products is divided by the time the wheat is fed into the first bran mill, and the quotient obtained is the feeding rate. 5.3.4 Sieve the flour using a 163μmnitex screen or a stainless steel screen with the same mesh size, and mix it in a closed container. Invert the container 25 times or more to make the sample mixed evenly.
5.4 Steady flow method
5.4.1 Place 1000g of wheat in the hopper of the mill. When the wheat has completely passed through the hopper, cut off the power supply, loosen the grinding rollers, and discard all the products. 5.4.2 Weigh another 1000g sample and place it in the hopper. Start the mill and immediately close the grinding gate. When the hopper is empty, stop grinding and loosen the grinding rollers. Weigh all the products. 3)
5.5 Detailed description of the characteristics of various grinding materials For detailed description of the characteristics of grinding materials, see Appendix A. 6 Preparation of wheat flour samples
According to the required flour extraction rate, weigh the flour in the order of 1B+1M, 2B+2M3B+3M, stir it thoroughly, pass it through a 163μm sieve for multiple times to mix it, and store it in a cloth bag or paper bag. After 14 days in summer and 21 days in winter, when the quality is stable, it can be used for dough property tests and food processing tests. Combine the remaining flour from 3B+3M with the bran powder and mix well to make the second flour. 7 Calculation
7.1 Flour extraction
It can be calculated based on the total recovered product or the wheat for grinding. All products should be corrected to 14% moisture basis and expressed on the same moisture basis.
7.2 Flour extraction calculation see Appendix B.
1) Installing an impactor between two core mills can increase the flour extraction of medium hardness wheat without affecting the quality of the flour. 2) Because a large amount of air passes through the air transport system of the mill, the moisture content, flour extraction rate and other characteristics of the flour are very sensitive to the environment in the milling room. In order to obtain accurate results, the temperature and humidity of the milling room should be controlled. 3) Although the flour is made by the steady flow method, the sieve of the experimental mill can maintain a steady flow, and it is not necessary to clean it completely between two samples, so there is less contamination. However, a large amount of wheat sample is required to thoroughly clean the previous sample. 3
NY/T1094.22006
A.1 Bran
Appendix A
(Informative Appendix
Detailed description of the characteristics of various grinding materials
A.1.1 Bran size (size): large flakes, general, broken: A.1.2 Bran cleanliness (cleanness): refers to the degree of white spots (endosperm attached to the bran), few, general, many: A.1.3 Bran thickness (thickness): thick, general, thin. A.2 Shorts
A.2.1 Amount of shorts (amount): low, general, excessive; A.2.2 Character of shorts (character): general, or flaky, that is, containing small pieces of endosperm 1). The shorts contain too much flour, that is, the shorts contain more flour, or are fluffy.
A.3 Materials and sieving characteristics (Middlings and sieving characteristics) A.3.1 Sharp: indicates less powder, usually horny; A.3.2 Mealy: usually soft, starch structure: A.3.3 Friable: easy to break when grinding, a large amount of flour can be extracted when sieving: A.3.4 Woolly: softer or fibrous; A3.5 Not easy to break when grinding: a large amount of flour cannot be extracted when sieving. A.4 Recommended milling conditions (Recommended milling conditions) A.4.1 Moisture adjustment degree (temper level): low, general, high; A.4.2 Feed rate (feed rate): low, general, high; A.4.3 Roll distance (roll settings): loose, general, tight; A.4.4 Flour rating (rating): excellent, good, general, inferior. 1) The reason is that the moisture content of tempered wheat is too high, the feeding speed is too fast during the back grinding, the pressure of the center mill roller is too high, or it is a combination of the above reasons. 4
B.1 Flour-bran ratio
Flour-bran ratio is calculated according to formula (B.1):
Wherein:
Flour-bran ratio flour extraction rate;
Appendix B
(Informative Appendix)
Flour extraction rate calculation
mB+mM+mz
m+mm+mz+ms+mc
Mass of 1B flour + 2B flour + 3B flour, in grams (g); Mass of 1M flour + 2M flour + 3M flour, in grams (g): Mass of secondary flour, in grams (g);
Mass of fine bran after brushing bran, in grams (area); Mass of coarse bran after brushing bran, in grams (g). Net wheat flour extraction rate
The net wheat flour extraction rate is calculated according to formula (B.2):
Wherein:bZxz.net
Net wheat flour extraction rate;
Xx=P+ mM+mz×100%
-1B flour+2B flour+3B flour mass, in grams (g):-1M flour+2M flour+3M flour mass, in grams (g); inferior flour mass, in grams (g);
Mass of net wheat ground by one person, in grams (g). B.3 Ash transfer rate
The ash transfer rate is calculated according to formula (B.3):
Wherein:
X3——ash transfer rate;
Ash rate of wheat ground by one person, %;
Ash rate of all flour, %;
Flour bran ratio flour extraction rate.
B.4 The ratio of skin-ground powder to core-ground powder (BM rate) X=r-w2
The ratio of skin-ground powder to core-ground powder is calculated according to formula (B.4): X100%
NY/T1094.2—2006
NY/T1094.2—2006
Wherein:
mB×100
BM(%)
The ratio of skin-ground powder to core-ground powder, %;
-1The mass of B powder + 2B powder + 3B powder, in grams (g); The mass of 1M powder + 2M powder + 3M powder, in grams (g). (B.4)
C.1 Maintenance of the laboratory mill
Appendix C
(Informative Appendix)
Precautions for Bihler laboratory milling
NY/T1094.2—2006
When not in use for a long time, to prevent the mill from rusting, apply a thick layer of butter on the surface, and wash it with gasoline when in use. Take out the screen cloth and the suction-type cloth drum filter bag and clean them thoroughly. To prevent insect damage, put insect repellent and seal it. C.2 Feeding speed
It is best to complete the milling as soon as possible without reducing the flour yield and quality. The feeding speed of medium-hard hard wheat is more suitable at 100g/min~130g/min: the feeding speed of soft wheat is more suitable at 60g/min~80g/min. C.3 Sieve
The effect of the sieve on the flour extraction rate is greater than that of the grinding roller pitch and the feeding speed, so the number of the sieve used must be indicated. In addition, pay attention to the tension of the belt in the sieve rotating device to make the sieve operate normally as much as possible. C.4 Preparation of 60% wheat flour for testing: weigh 60% of the amount in the order of 1B+1M, 2B+2M, 3B+3M, stir well, and pass it through a 163mm sieve for multiple times to mix. Take about 100g and place it in a small polyethylene bag, seal the bag mouth, and use it as a sample for analyzing components and measuring color. The remaining 60% is placed in a paper bag for storage. After 2 weeks in summer and 3 weeks in winter, it is used for dough performance tests and food processing performance tests after the quality is stable. In the test of wheat flour, sometimes all the flours of the 6 powder routes are mixed together (unified flour), but due to the different flour extraction rates, it often has a great impact on the evaluation of flour test results. When using experimental mill flour for noodle processing tests, flour with a flour extraction rate lower than 60% (40%~50%) is sometimes used.
C.5 Flour extraction rate can be calculated by raw wheat flour extraction rate, flour-bran ratio, and net wheat flour extraction rate. When conducting comparative tests of 1000g~3000g varieties, the flour-bran ratio has a smaller error variance and is easy to detect the differences between different samples. C.6 The ash content of all flour is determined by measuring the ash content of 60% flour and second flour respectively, and then calculating the ash content of flour according to the mass ratio. C.7 The ash content of flour and bran is very different. It can be considered as a superb milling technology to transfer the ash of raw wheat to bran as much as possible. It also shows that the cortex and endosperm of this type of wheat are easy to separate. Therefore, the larger the value of the ash transfer rate, the more exquisite the milling technology and the better the milling performance of wheat.
C.8 Flour milling loss
Depending on the type of wheat, the temperature and humidity of the laboratory, it is generally about 2%-8%. If the loss is too large, it is best to retest. C.9 When conducting comparative tests, the samples to be compared should be milled on the same day, or part of the samples should be added every day for comparison. The fine bran contains flaky endosperm, which is caused by excessive water addition, too fast feeding speed of the mill, excessive milling pressure, or a combination of the above factors.
C.10 The number of repetitions required to evaluate the differences between different samples in the Buhler experimental mill flour test is shown in Table C.1 NY/T1094.2—2006
1 The number of repetitions required to test the differences between different samples in the flour test (Buhler flour mill) Table C
Characteristic values
Flour extraction rate (absolute flour extraction rate)
Total flour content
Grinding results
Coarse flour yield
Crude bran ash content
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